1. Field of the Invention
The present invention relates to a toothbrush, which is capable of absorbing excessive force added to a toothbrush and effectively cleaning recessed and projected portions of teeth as well as the space between them, and provided with an attachable and detachable brush base.
2. Background Art
There are various conventional arts related to a toothbrush including the one that controls the force added to a toothbrush, or the one that applies an elastic member to the brush fixing portion or to the brush base so as to effectively clean the recessed and projected portions of teeth, or the one that infuses vapor or liquid into a bag beneath the brush-fixing portion in place of an elastic member so as to control the force added to the toothbrush. For example, as described in Japanese Utility Model Laid-Open Publication Showa 51-110761 (1976), there is such a prior art that applies an elastic member to the brush base, or the one that buries brush bundles into an elastic member as described in Japanese Patent Laid-Open Publication 2001-190333, or the one that uses an elastic body filled with vapor or liquid as described in Japanese Patent Laid-Open Publication 2001-8735. Further, Japanese Patent Laid-Open Publication Heisei-06-304022 (1996) describes a toothbrush, which is provided with an attachable and detachable brush base fitted with brush bundles so as to help promoting economy and saving resources. Reference patent documents:
With reference to any conventional toothbrush, in order to absorb the force added to the toothbrush so that an average force of the brush bundles can be applied to recessed and projected teeth, there are various toothbrushes including the one that buries brush bundles into an elastic member, or the one that aims at absorbing the force added to brush bundles by securing an elastic member beneath the brushes. However, unless the elasticity varies, none of these conventional toothbrushes can achieve the aimed utility. Hence, in order to secure a correct amount of the recesses and projections of teeth via an elastic member, it was quite essential that the thickness of an elastic member or body be increased. Further, in order to achieve the intended object by elongating the elastic member, it was required to use a soft elastic member so as to secure a proper elongation amount. As a result, elasticity lost own effect by a maximum extent when no pressure was added to the brush-fixing portion to cause brush bundles to topple themselves by a maximum degree. Conversely, when aiming at securing a greater amount of elasticity, it in turn requires much time to restore the proper state of brush bundles after being subject to an elastic action. Further, when any of the brush bundles enters into the space between teeth or when finely performing a brushing process, proper function of the toothbrush can hardly be exerted. In the case of such a toothbrush fitted with an elastic member at an upper portion of the stem of the toothbrush head component, structurally, it is rather difficult to contract the corresponding toothbrush head component, and thus, it is inappropriate for a user to effectively apply a thin head component to the brushing. With reference to such a toothbrush capable of attaching and detaching a brush base fitted with brush bundles, it is considered that the stem thereof is durable for a period longer than that of the conventional toothbrushes. It is an object of the above toothbrush capable of attaching and detaching the brush base fitted with brush bundles so as to solely replace consumable brush bundles fixed to the brush base without wasting material resources so as to help saving these resources via economy and cost reduction to be advantageous on the part of consumers as well as toothbrush manufacturers.
Japanese Utility Model Laid-Open Publication Showa 51-110761 (1976), refers to a toothbrush, which is provided with brush bundles inside and above an elastic member secured onto a stem of a toothbrush head component. In order to achieve the intended object and secure a proper amount of elasticity, the toothbrush uses a soft and relatively thick elastic member. As a result, when pressure was added to the brush bundles, the elasticity at the brush-fixing portion became the least, thereby causing the brush bundles to topple themselves by a substantial extent, thus indicating that this toothbrush was not suitable for performing a brushing process when insubstantial pressure was added to teeth. For example, since no pressure is added to brush bundles that are caught between teeth, due to substantial toppling effect generated at the brush-fixing portions, in particular, when finely performing a brushing process, actual brushing effect is practically lost. It is said that a substantial amount of pressure should be added to teeth, in principle, approximately 200 grams of pressure should be added thereto as an appropriate amount. When no pressure is added to teeth, teeth cleaning effect is hardly achievable. It was clarified via an observation on the behavior of the elasticity that the most remarkable toppling effect was generated at the brush-fixing portion before the elasticity became variable. Hence, it was identified that, relatively to the contraction of the elasticity, elastic property of the elastic member was strengthened to cause the elastic member to be contracted. Conversely, the softer the elastic member, the more the pressure added to the brush bundles can be absorbed. Nevertheless, it in turn requires much time to restore the initial state of the brush bundles that incurred elastic deformation, thereby disabling the toothbrush to quickly and effectively deal with variations caused by the recesses and projections of teeth during a brushing process.
Japanese Patent Laid-Open Publication 2001-190333 refers to a toothbrush that has an elastic member at the brush-bundle fixing portions, where the elastic member inclusive of the elongated configuration is designed to incline itself so as to enable the brush bundles to effectively contact the recessed and projected portions of teeth. Nevertheless, in order to finely perform a brushing process, since the brush bundles are obliquely configured, pressure added to teeth is externally rejected from those brush bundles caught in the space between teeth or in the recessed portions thereof, and thus, the toothbrush cited in Japanese Patent Laid-Open Publication 2001-190333 is inappropriate for practical use. Like the case cited in Japanese Utility Model Laid-Open Publication Showa 51-110761 (1976), the elastic member becomes the softest while the elastic member remains free from the elastic deformation. In other words, the higher the amount of the elastic deformation, the higher the hardness of the elastic member. In order to enable the brush bundles to effectively contact the recessed and projected teeth with an average pressure, unless such a soft elastic member having ductile property or shrinkable property is used, the aimed object can hardly be achieved. Further, in this case, it takes much time for restoring the initial state of the brush bundles by a period longer than the case of using a hard elastic member, and so, the prior toothbrush cited in the above patent document 2 is inappropriate for practical use.
Japanese Patent Laid-Open Publication 2001-8735 refers to such a toothbrush, which is capable of controlling pressure of an elastic member filled with vapor or liquid beneath the brush-fixing portions so that the aimed object can be achieved. However, the above toothbrush consists of a complex structure and can hardly secure stable elasticity. In the case in which the elastic member is filled with vapor for example, depending on the difference in the atmospheric pressure, actual locations, variation of atmospheric temperature, water temperature, or body temperature, or due to the rise of vapor pressure caused by repeated elastic deformations, actual vapor pressure inside the elastic member is variable while performing a brushing process, thereby causing the elasticity to be variable likewise. When vapor leaks out from the elastic member, the elastic member incurs deformation without being restored into the initial state, and yet, it incurs infiltration of water. Even when vapor remains without leakage, there may be such a case in which the elasticity could vary itself due to variation of temperature or atmospheric pressure, or else, water drops or dew may be generated. Occurrence of these phenomena leads users to feel concern about unhygienic outcome. Above all, intrinsic stable elasticity will be lost in the above cases. Even if it is possible to retain the variable vapor pressure to be constant, the above toothbrush involves much difficulty to deal with. Even in the case of such an elastic member filled with liquid, much time is required to cause the liquid to flow itself, and yet, it also takes much time to enable the elastic member to restore the initial state after incurring deformation. If the liquid leaks out from the elastic member, it prevents the elastic member from restoring the initial state. These phenomena are quite similar to those took place in the toothbrush cited in Japanese Utility Model Laid-Open Publication Showa 51-110761 (1976). The complex structure of the toothbrush cited in Japanese Patent Laid-Open Publication 2001-8735 involves the rise of production cost and potential leakage of liquid as a crucial issue against preservation of oral sanitation for consumers.
Japanese Patent Laid-Open Publication Heisei-06-304022 (1996) refers to such a toothbrush, which is capable of optionally attaching and detaching the brush base to and from the toothbrush head component. The brush base is replaceable. This toothbrush has the aimed object and practical effect similar to those of the replaceable brush base related to the present invention. Up to the present, in order to form the brush base, the above toothbrush has been using a hard synthetic resin consisting of a quality close to that of the material of the stem of the toothbrush head component. Hence, whenever repeating processes for attaching and detaching the brush base, due to the friction generated between the brush base and the head component, the brush base fixing portion of the stem of the head component is worn off. Further, if there were even the slightest space between the stem of the head component and the brush base fixing portion, it will cause mutual friction to occur during the teeth brushing process. This in turn causes the teeth brushing duration to be prolonged, and yet, expands the toppling extent before eventually causing the brush-base fixing portion of the stem of the head component to be worn off otherwise should securely be avoided. Due to these reasons, after using the above toothbrush for a long while, there is a potential fear of generating unpleasant feeling caused by unwanted oscillation generated by the toppling during a teeth brushing process or potential fear of causing the newly replaced brush base to be disengaged easily.